1. Field of the Invention
The present invention pertains generally to shoe inserts. More particularly, the present invention pertains to orthotics useful for accommodating and treating foot abnormalities and methods thereof for mass producing orthotics in a manner choosing specific orthotics for a specific person. The preferred embodiments of the present invention are particularly, but not exclusively, useful as custom-made orthotics having selectable support portions, the orthotics being mass-producible.
2. Description of the Prior Art
Biomechanics relating to the human foot and potential abnormalities thereof are well known. FIG. 1 illustrates a skeletal bone structure of a human foot 10 composed of twenty-six bones that articulate with respect to one other by means of joints. The skeletal arrangement of the foot 10 provides for flexible support for the weight of the entire body. There are seven tarsal bones 2, the largest and the strongest of which is the calcaneus 4 (or heel bone), and serves to transmit the weight of the body to the ground and forms a strong lever for the calf muscle. The metatarsals 6, or sole and instep of the foot 10, is formed by five bones, each articulating with the tarsal bones 2 by one extremity, and by the other with the first row of phalanges 8.
The tarsal 2 and metatarsal 6 bones each form two distinct arches. As illustrated in FIG. 2, the first is the longitudinal or the plantar arch 11 that runs from the heel 4 to the ball 12 on the inner (medial) side and underside aspect of the foot 10. The other arch is a transverse arch across the forefoot in the metatarsal region 6.
Over-pronation, or flatfeet, is a common biomechanical problem that occurs in the walking process when a person's plantar arch 11a collapses upon weight bearing, as illustrated in FIG. 3A. Such over-pronation is a very common structural deformity in which there is outward rotation of the heel 4 (as shown in FIG. 3C) lowering the longitudinal arch 11a, displacing of the head of the first metatarsal dorsally, pronating and abducting of the distal part of the foot 10, resulting in an everted position of the heel. This movement can cause extreme stress or inflammation on the plantar fascia, potentially further causing severe discomfort and leading to other foot problems. Pain may be present in the plantar arch 11a or frequently localized in the area behind the medial malleolus. This results in the radiation of pain to the Achilles tendon, medial and posterior calf muscles, or up to the shin, knee, hip, and lower back.
As viewed from the bottom of the foot 10, FIG. 3B illustrates a height of a longitudinal arch 11 by comparing the position of an arch line AR or AR′ of the footprint with respect to the position of the reference line X, which is a straight line extending from the center of the second toe 13 to the center of the heel end 15. When the arch line of a footprint is above the reference line X as shown by the dotted line AR′, the foot arch 10 is estimated to be relatively low. On the other hand, when the arch line of a footprint is below the reference line X as shown by the solid line AR, the foot arch 10 is estimated to be relatively high. Line X is used as a base line in the estimation due to the weight of a person being typically concentrated near the second toe 13 and near the outer portion of the heel end 15 during walking or running.
The body's kinetic chain of imbalance starts with abnormally low arched feet meeting the ground, followed by a cascade of interdependent physical reactions involving twisting, pulling and compressing of predictable muscle groups, tendons, ligaments, and bones from the bottom of the feet to the top of the skull. The abnormal position of the feet (low arch height AR′) does not allow physical stress to travel vertically from the feet upwards towards the hip sockets. Therefore, as is illustrated in FIG. 3C viewing from the rear of a user's feet, the vertical stress line 14 of heel 4 for a flatfoot forms an acute angle to the ground, and is not at a perpendicular thereto.
Flatfeet can potentially lead to a variety of diseases including for example, plantar fasciitis, metatarsalgia, sesamoiditis, Morton's neuroma, heel spurs, achilles tendinitis, posterior tibial tendinitis, shin splints, bunions, knee, leg, hip, lower and upper back, shoulder, and neck pains, including headaches, and others. Heretofore, shoe inserts or insoles have been used to alleviate some of the pain caused by flatfeet. However, the prior art insoles are not a corrective measure, but merely an accommodating one. In other words, the insoles do not correct arch deformities; but rather merely accommodate to help alleviate some of the pain caused by the deformity.
Generally in the orthotic art, in order to make custom-made shoes or insoles for flatfeet, a cast is first taken of a foot using a plaster bandage. Next, custom-made orthotics or insoles are made by molding over the plaster foot cast with synthetic resins or other materials. Of concern, some of the materials used for the construction of the prior art orthotics are not suitable for insoles; they may include leather, graphite, cork, steel, aluminum, and even wood. Furthermore, the prior art orthotics require too much time and often-complicated procedures to make, and are costly. Moreover, it is impossible to mass-produce plaster casted orthotics.
Other processes contemplated in the art include analyzing the foot's individual pressure points with respect to the ground to make an insole with a structure (or shape) that accommodates those measured pressure points. Accordingly, pre-molded insoles are produced that comprise individual pads for each of these pressure points. These may include a pair of flat insole plates that have a convex shape corresponding to the arch of the sole, a pair of forefoot pads accompanying each of the insole plates, a pair of rear-foot pads, a pair of longitudinal pads, and further a pair of auxiliary pads. All are to be attached on the insole plates to compensate the uneven contact of the foot with the ground. Although mass producible, the pad accompanying plates have problems fitting certain feet. Many parameters are required to be considered when these pads are attached on the insole plate, such as structural or anatomical foot variances, or the almost impossible task to control the foot angle to the ground surface with semi-pronating or hyper-pronating feet. Therefore, there is a strong need for advancement in shoe insoles (i.e. orthotics) that are easily employed inside shoes, and a means of foot correction and underfoot comfort for the abnormal foot.
In light of the above, it is an object of the present invention to provide a design of orthotics that is able to be custom made and adaptable to a particular user's needs based on factors such as type of footwear in addition to user's age, weight, foot size, activity level and foot abnormality.
It is yet a further object of the present invention to provide an orthotic having design choices for thickness of and rigidity of material.
Yet another object of the present invention is to provide a system of assembling custom made, mass producible orthotics that is easy to manufacture, relatively simple to use and comparatively cost effective.